1. Field
The present specification generally relates to strengthened glass substrates and, more specifically, to ion-exchange strengthened glass substrates with glass frits applied to at least a portion of the surface and methods for making the same.
2. Technical Background
Ion exchange strengthening is used to improve the mechanical resistance of glass in numerous applications ranging from hand-held consumer smart-phones and electronic tablets to automotive glazing. Ion exchange strengthening is of particular interest in automotive glazing. Conventional automotive glazing is typically formed from soda-lime silica glass that has been thermally tempered to induce a surface compressive stress and improve the resistance of the glazing to mechanical failure following damage such as scratches, chips or the like. However, the amount of residual compressive stress imparted by thermal tempering is not high (on the order of 200 MPa-300 MPa). Accordingly, automotive glazing needs to be relatively thick to assure that the glazing will withstand high mechanical loads before failure occurs.
Ion exchange processes generally impart a greater amount of compressive stress (typically on the order of 600 MPa to 800 MPa) to glass articles compared to thermal tempering processes. Accordingly, ion exchanged glass articles generally have a greater resistance to mechanical failure than similar glass articles which are thermally tempered. This means that the ion exchanged glass articles may be formed with a reduced thickness while still retaining the same or even improved resistance to mechanical failure relative to thermally tempered glass articles.
However, in the case of automotive glazing, the compressive stress introduced by ion exchange may be diminished during subsequent processing steps, such as the application of glass frit to the surface of the automotive glazing, thereby mitigating the benefits of ion exchange strengthening.
Accordingly, a need exists for alternative strengthened glass substrates with glass fits which retain the benefits of ion exchange strengthening.